Self-aligning termination for memory alloy wire

ABSTRACT

A self-aligning memory alloy wire actuator has a memory alloy wire having first and second ends with at least one terminal coupled to one end of the memory alloy wire. The terminal includes two wings and an extended piece connected in the shape of a T. The two wings are disposed on opposite sides of the extended piece and perpendicular to the extended piece. Each wing comprises top and bottom surfaces, a front surface, and an outside end. The top surfaces of the two wings lie on a common top plane and the front surfaces of the two wings lie on a common front plane. The memory alloy wire is coupled to the extended piece of the terminal.

BACKGROUND

1. Field

The present disclosure generally relates to systems and methods ofactuation, and, in particular, relates to the actuators utilizing memoryalloy wire.

2. Description of the Related Art

Providing secure storage frequently requires a container with a lid thatis released only after certain requirements are met, such asverification that the individual accessing the container is authorizedto do so. Systems of this type use an actuator of some type to release alatch that otherwise retains the lid in the closed position. Commonactuators include solenoids and motors, both of which may be relativelylarge compared to the usable volume of the container, which decreasesthe volumetric efficiency of the container.

Actuators that utilize memory alloy wire can provide sufficient powerand stroke to release the latch of a secure container while occupyingless volume than a solenoid or motor. Memory alloy wire, also known as“muscle wire,” is made from one of a number of alloys that contract inlength when heated and can be stretched back to their original lengthwhen cooled back to room temperature. Example alloys includenickel-titanium alloys that were first developed by the US NavalOrdnance Laboratory and commercialized under the trade name Nitinol(taken from the words Nickel Titanium Naval Ordnance Laboratories). Thememory alloy wire is commonly heated by passing an electric currentthrough the wire, creating heat within the wire due to the internalresistance of the wire.

When used as an actuator, a length of memory alloy wire typically has aterminal attached to each end of the wire. Commonly available memoryalloy wire actuators have terminals that attach to posts on printedcircuit board assemblies (PCBAs) and serve as the electrical contact forthe current that heats the memory alloy wire as well as the mechanicalattachment. The PCBA is then mounted to the same structure to which theother elements of the actuator are attached, adding another assemblytolerance to the system. One drawback of current memory alloy wireactuators is that shape memory strain is typically limited to 5%, whichtranslates to a maximum stroke of 0.100 inches for a 2 inch actuator.This stroke can easily be consumed by the sum of multiple assemblytolerances, leaving little usable stroke for the actual releasefunction. An additional drawback is that the memory alloy is sensitiveto fatigue at points of stress concentration due to bends in the wire atthe point of electrical termination.

U.S. Pat. No. 6,116,461, Method and Apparatus for the Dispensing ofDrugs, Broadfield et al., discloses an Automated Dispensing Machine(ADM) that utilizes a memory alloy wire actuator. While this system wasa significant advance in the dispensing of medications, the memory wireis directly and rigidly attached to the PCBA as described above. Assuch, the memory alloy wire actuator does not reach its full potential.

SUMMARY

In order to provide a more robust and reliable actuator, it isadvantageous to provide a memory alloy actuator having terminals thatself-align with the memory alloy wire, thereby reducing the bendingstress on the memory alloy wire and increasing the life of the actuator,and provide for mounting directly to the body of the container, therebyreducing the tolerance stack of the assembly. The disclosed systemincludes a memory wire actuator incorporating self-aligning terminalsthat provide such benefits.

A memory alloy wire actuator is disclosed that comprises a memory alloywire having first and second ends with at least one terminal coupled toone end of the memory alloy wire. The terminal includes two wings and anextended piece connected in the shape of a T. The two wings are disposedon opposite sides of the extended piece and perpendicular to theextended piece. Each wing comprises top and bottom surfaces, a frontsurface, and an outside end. The top surfaces of the two wings lie on acommon top plane and the front surfaces of the two wings lie on a commonfront plane. The memory alloy wire is coupled to the extended piece ofthe terminal.

A memory wire actuator assembly is disclosed that comprises a memoryalloy wire actuator and a retention feature. The memory alloy wireactuator comprises a memory alloy wire and at least one terminal coupledto one end of the memory alloy wire. The memory alloy wire has first andsecond ends. The terminal has two wings and an extended piece connectedin the shape of a T. The two wings are disposed on opposite sides of theextended piece and are perpendicular to the extended piece. Each winghas top and bottom surfaces, a front surface, and an outside end. Thetop surfaces of the two wings lie on a common top plane and the frontsurfaces of the two wings lie on a common front plane. The memory alloywire is coupled to the extended piece of the terminal. The retentionfeature comprises a planar surface and a notch that passes through theplanar surface. The front surfaces of the wings of the terminal contactthe planar surface of the retention feature such that the extended pieceof the terminal passes through the notch.

A self-aligning terminal is disclosed that comprises a cross-piecehaving a center and two wings connected to the center and extending inopposite directions from the center. The wings each comprise a topsurface that lie in a common top plane. An extended piece is connectedto the center of the cross-piece and extends perpendicular to the wings.Each wing further comprises a front surface facing towards the extendedpiece wherein the front surfaces of the two wings lie in a common frontplane. The extended piece is configured to couple to a memory alloy wireat a point separated from the common front plane.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide furtherunderstanding and are incorporated in and constitute a part of thisspecification, illustrate disclosed embodiments and together with thedescription serve to explain the principles of the disclosedembodiments. In the drawings:

FIG. 1 is a partially exploded view of a lidded container according tocertain aspects of this disclosure.

FIG. 2 depicts a lid release mechanism according to certain aspects ofthis disclosure.

FIG. 3 depicts the lid release mechanism of FIG. 1 in the unlatchedposition according to certain aspects of this disclosure.

FIG. 4 depicts the lid release mechanism of FIG. 1 as the lid is beingclosed according to certain aspects of this disclosure.

FIG. 5 depicts a memory alloy wire actuator according to certain aspectsof this disclosure.

FIGS. 6A-6C depict an exemplary memory alloy wire terminal according tocertain aspects of this disclosure.

FIG. 7 depicts a retention feature of a memory alloy wire actuatorassembly according to certain aspects of this disclosure.

FIG. 8 illustrates an exemplary memory alloy wire actuator assemblyacting on an actuation element according to certain aspects of thisdisclosure.

FIGS. 9A-9D illustrate the operation of a self-aligning terminal of amemory alloy wire actuator assembly according to certain aspects of thisdisclosure.

FIG. 10 illustrates an exemplary retention feature configured toposition the self-aligning terminals parallel to and offset from eachother according to certain aspects of this disclosure.

FIG. 11 illustrates an exemplary ADM that includes removable liddedcontainers that include memory alloy wire actuators according to certainaspects of this disclosure.

DETAILED DESCRIPTION

The disclosed embodiments of memory alloy wire systems provide aself-aligning capability for the memory alloy wire that reduces bendingstresses and increases the operational life of the actuator.

In the following detailed description, numerous specific details are setforth to provide a full understanding of the present disclosure. It willbe apparent, however, to one ordinarily skilled in the art thatembodiments of the present disclosure may be practiced without some ofthe specific details. In other instances, well-known structures andtechniques have not been shown in detail so as not to obscure thedisclosure.

The method and system disclosed herein are presented in terms of acontainer having a lid with a hook that is retained by a releasemechanism. It will be apparent to those of ordinary skill in the artthat the disclosed concepts may be applied to a variety of mechanismsutilizing memory alloy wire. Nothing in this disclosure should beinterpreted, unless specifically stated as such, to limit theapplication of any method or system disclosed herein to latch or closuremechanisms.

FIG. 1 is a partially exploded view of a lidded container 1 according tocertain aspects of this disclosure. The container 1 comprises a body 2and a lid 50 that is hingedly attached to body 2 through engagement ofpivot pins 50A with the pin capture features 1A. When the lid 50 isclosed, lid hook 52 passes through the hole 2A in body 2 and comes intoproximity with the latch release mechanism 10 that is visible in FIG. 1within a front compartment of body 2 (a front cover plate of body 2 hasbeen omitted to make visible the latch release mechanism 10).

FIG. 2 depicts the latch release mechanism 10 according to certainaspects of this disclosure. The latch release mechanism 10 is configuredto retain lid 50 in a closed position when in the position shown in FIG.2. The fixed elements of latch release mechanism 10 are attached to body2 (not shown in this view) and therefore fixed in position andorientation relative to the lid 50 and to each other. Latch lever 4 hasrotated in a clockwise direction about a fixed pivot 5 such that latchhook 4A, which is located on the end of one of the arms of latch lever4, has engaged the lid hook 52. Spring 7 applies a force to latch lever4 that causes a clockwise torque about pivot 5 to be applied to latchlever 4, maintaining the latch lever 4 in the position shown in FIG. 2.

The latch release mechanism 10 includes a memory alloy wire actuator 20which wraps around capstan 13. Capstan 13 is in contact with one end ofplunger 12, the other end of plunger 12 being in contact with latchlever 4. The terminals 22 of memory alloy wire actuator 20 are mountedto the body 2, with details of the mounting discussed in relation tolater figures. The length of memory alloy wire actuator 20 limits therange of travel of capstan 13 to the right, which then limits the motionof plunger 12 and consequently the clockwise rotation of latch lever 4.The torque applied by spring 7 causes the latch lever 4 to rotateclockwise until it reaches this limit. The mounting location ofterminals 22 and the dimensions of capstan 13, plunger 12, and latchlever 4 are chosen to cause the latch hook 4A to be in this “latched”position, wherein latch hook 4A is engaged with latch hook 52 withoutapplying a lateral force to the latch hook 52. When in the latchedposition, the torque applied by spring 7 applies a force to plunger 12and thereby to capstan 13, which then transfers this force to the memoryalloy wire 24 of the memory alloy wire actuator 20, placing the memoryalloy wire 24 in tension.

FIG. 2 also depicts how the memory alloy wires 24 are electricallyconnected. One of the memory alloy wires 24 is shown connected toelectrical terminal 19. Electrical terminal 19, in this embodiment, is asolderless compression connector wherein the two arms 19A and 19B areformed with a slot 19C between them, as seen in the view A-A of FIG. 2.The width of the slot 19C is less than the diameter of memory alloy wire24. Arms 19A and 19B are made of a conductive material and are formedsuch that they have a low spring constant in the direction perpendicularto slot 19C. The electrical connection is made by sliding memory alloywire 24 sideways into the slot 19C, which deforms both arms 19A and 19Bplacing the memory alloy wire 24 in compression between the arms 19A and19B. This compressive contact is sufficient to form a conductive bondbetween the arms 19A, 19B and the memory alloy wire 24. If a voltage iscreated between electrical terminal 19 and a similar electrical terminal(not shown) connected to the other end of memory alloy wire 24, acurrent will flow through the memory wire 24, heating the memory alloywire 24 and causing the memory alloy wire 24 to contract. In certainembodiments, this electrical contact is accomplished with any of aplurality of electrical contact terminals known to those of skill in theart, including screw terminals and solder terminals.

The latch release mechanism 10 also includes a cantilever 6 that rotatesabout a fixed pivot 9. While the configuration of cantilever 9 isdiscussed here, the purpose of cantilever 9 is disclosed in discussionof later figures. At one end, cantilever 9 engages a feature of plunger12 at the same point that plunger 12 contacts capstan 13. A cantileverspring 8 applies a force to the other end of cantilever 9. This forcecreates a clockwise torque about the pivot 9, which rotates cantilever 6about the pivot causing the first end to push plunger 12 towards thecapstan 13 which is constrained from further lateral motion by thememory alloy wire actuator 20. The force applied by cantilever 6 toplunger 12 is applied parallel to and additive with the force applied bylatch lever 4 to the plunger 12 and the sum of these forces is appliedto capstan 13.

The latch lever 4, plunger 12, and cantilever 6 form a 4-bar linkagewith the fourth element being the body 2 to which the latch lever 4 andcantilever 6 are pinned. The plunger 12 is configured such that, overthe range of motion of the memory alloy wire actuator 20, the plunger 12moves approximately along the line of action of the memory alloy wireactuator 20. This reduces side-to-side angular displacement of thememory alloy wire 24 and improves the operational life of the memoryalloy wire actuator 20 and keeps the portions 24A, 24B (furtherdescribed in relation to FIG. 8) of the memory alloy wire actuator 20equal to prevent slippage of the memory alloy wire 24 around the capstan13.

In operation, lid 50 is released when a current is passed through memoryalloy wire actuator 20. The memory alloy wire 24 contracts due to theconversion from its martensite form to its austenite form caused byheating induced by the current passing through the resistance of thememory alloy wire 24. This contraction force is applied to capstan 13 inthe direction opposing the forces applied by plunger 12 and cantilever6. As the memory alloy wire 24 contracts, capstan 13 moves to the leftcausing latch lever 4 and cantilever 6 to rotate counterclockwise,releasing the lid hook 52, which allows the lid 50 to open under theinfluence of the lid springs (not shown). When the opening of the lid 50is detected by a lid sensor (not shown) the current through memory alloywire 24 is shut off.

FIG. 3 depicts the latch release mechanism 10 of FIG. 2 in the unlatchedposition according to certain aspects of this disclosure. In thisexample, the memory alloy wire actuator 20 has sufficient currentflowing through the memory alloy wire 24 from an external circuit (notshown) to cause the memory alloy wire 24 to contract approximately 2%,which is a commonly used target contraction value for memory alloy wire.In certain embodiments, the memory alloy wire 24 contracts 3.5%. Thecontraction has overcome the force applied by the plunger 12 andcantilever 6 and displaced capstan 13 and plunger 12 to the left,rotating latch lever 4 sufficiently to disengage lid hook 52 and therebyrelease lid 50. In this example, the lid 50 is spring-loaded and the lid50 will self-open upon release of lid hook 52.

FIG. 4 depicts the latch release mechanism 10 of FIG. 1 as the lid 50 isbeing closed according to certain aspects of this disclosure. As the lid50 closes, the angled underside of lid hook 52 comes into contact withthe top corner of latch lever 4, rotating the latch lever 4counterclockwise. This rotation compresses spring 7 but does not pullplunger 12 to the right, as the engagement of plunger 12 with latchlever 4 is through pin 12A which fits into slot 4B. While clockwiserotation of latch lever 4 applies a compressive force to plunger 12through pin 12A, counterclockwise rotation does not create a tensionforce in plunger 12 as pin 12A is not attached to latch lever 4. Aslatch lever 4 rotates counterclockwise, the slot 4B pulls away from pin12A, which is maintained in its original position by the force appliedby the cantilever 6 to the other end of plunger 12. Slot 4B is longenough that pin 12A does not disengage from the slot 4B as the lidcloses.

The force applied by cantilever 6 maintains tension in the memory alloywire 24 while the lid is being closed, which is the primary function ofcantilever 6 and cantilever spring 8. Without cantilever 6 andcantilever spring 8, the tension in memory alloy wire 24 would go tozero as the latch lever 4 rotates during lid closure, which removes thecompressive force applied to plunger 12. In addition, without cantilever6 and cantilever spring 8, the memory alloy wire 24 would be subjectedto a shock load when the lid hook 52 passes below the lid hook 4A, asthe latch lever 4 would snap back to its original position under theinfluence of spring 7. Both the repeated loss of tension and the shockload that would be experienced by memory alloy wire 24 upon each lidclosure are detrimental to the operational lifetime of memory alloywire.

FIG. 5 depicts a memory alloy wire actuator 20 according to certainaspects of this disclosure. In this embodiment, the memory alloy wireactuator 20 comprises a length of memory alloy wire 24 with a terminal22 attached at each end. It can be seen that, in this embodiment, thememory alloy wire 24 extends past each of the terminals 22 such thateach end of the memory alloy wire 24 can separately and independently beconnected to a contact of electrical circuit. Thus, terminal 22 providesonly the mechanical attachment function and is decoupled from theelectrical contact function. As the contraction of the memory alloy wire24 is only a few percent, the distance between the terminals must beprecisely controlled to ensure that the latch hook 4A is properlylocated to engage lid hook 52 and able to disengage the lid hook 52within this limited amount of displacement. The memory alloy wireactuator 20 is formed into the “U” shape to provide twice the actuationforce of a single wire. The separation of the mechanical and electricaltermination functions allow for the optimization of the reliability ofthe mechanical termination.

FIGS. 6A-6C depict an exemplary memory alloy wire terminal 22 accordingto certain aspects of this disclosure. FIG. 6A is a plan view of aterminal 22 having the same features as the ones that are shown as partof the memory alloy wire actuator 20 of FIG. 5. Terminal 22 includes acrosspiece 25 and an extended piece 28, as indicated by the dashed lineboxes. Crosspiece 25 includes two wings 26 and 27 that are joined at thecenter and extend away from each other and perpendicular to the memoryalloy wire 24. The extended piece 28 is attached to the center ofcrosspiece 25 and extends perpendicular to wings 26 and 27. In thisexample, the wings 26 and 27 and the extended piece 28 are formed from asingle piece of metal. In certain embodiments, other wire attachmentmeans are utilized, such as the extended piece 28 being a separateelement that is coupled to the crosspiece 25.

FIG. 6C is a perspective view of the terminal 22 of FIG. 6A. Wings 26and 27 have top surfaces 26A and 27A, respectively, that lie in a commonplane. Wings 26 and 27 also have front surfaces 26B and 27B,respectively, that are adjacent to the top surfaces and lie in their owncommon plane. It is visible in this view that this embodiment ofextended piece 28 includes a crimp element 29 that has been folded overto capture and retain memory alloy wire 24. In certain embodiments, theextended piece 28 includes a separate attachment element, such as acrimp ring (not shown) that couples the memory alloy wire 24 to theterminal 22.

FIG. 6B is an end view of the terminal seen in FIG. 6A. It can be seenthat the top surfaces 26A and 26B, seen on edge in this view, lie in acommon plane that is perpendicular to the page. Wings 26 and 27 alsohave bottom surfaces 26C and 27C that lie in a common plane that isapproximately parallel to the plane of surfaces 26A-27A. Terminal 22 hasan effective cross-section area 26D that is defined as the area in thefront surface plane 26B-27B that is between the common top plane 26A/27Aand the common bottom plane 26C-27C and bounded on the sides by the endsof wings 26 and 27. Area 26D is indicated in FIG. 6B by the dashed linebox, wherein the box is shown as slightly larger than the area definedabove to improve the visibility of the box and is intended only to showthe general area defined above. It can be seen that, in this embodiment,extended piece 28 is offset relative to wings 26 and 27 such that thecross-section of memory alloy wire 24, when held in place by crimp 29,overlaps the effective cross-section 26D when the cross-section isprojected onto the common front plane along a line that is perpendicularto the cross-section. In certain embodiments, a line extended from thepoint of coupling between the memory alloy wire 24 and the terminal 22and in the direction of the centerline of memory alloy wire 24 at thatpoint passes through the area 26D. In certain embodiments, terminal 22is formed from a sheet that is thicker than memory alloy wire 24 and theentire projected cross-section of memory alloy wire 24 lies within area26D.

FIG. 7 depicts a retention feature 30 of a memory alloy wire actuatorassembly 40 of FIG. 8 according to certain aspects of this disclosure.The retention feature 30 is, in this example, formed as part of a basestructure (not shown) such as the body 2 of FIG. 1. In certainembodiments, the retention feature 30 is a separate part that is coupledto the base structure. Axis 31 is the line of action of a memory alloywire actuator 20 (not shown) and surface 32 is perpendicular to axis 31.A notch 34 is formed in retention feature 30 such that the axis 31approximately passes through the notch 34. The structure of retentionfeature 30 is sufficiently strong to resist breakage or bendingsufficient to allow the terminals 22 to slide off the retention feature30 under the influence of the compressive force applied by the memoryalloy wire actuator 20 to surface 32. In certain embodiments, a notch(not shown) is provided on the surface 32 where the terminal 22 willcontact the surface 32 to assist in locating and retaining the terminal22 in the desired position. In certain embodiments, other types ofpositioning and retention features, such as posts and tabs, are providedon or near surface 32.

FIG. 8 illustrates an exemplary memory alloy wire actuator assembly 40acting on an actuation feature 42 according to certain aspects of thisdisclosure. Actuation feature 42 is constrained to move approximatelyalong the line of action 31 of memory alloy wire actuator 20. Actuatorassembly 40 includes a memory alloy wire actuator 20 and, in thisembodiment, a retention feature 30 having two notches. In certainembodiments, this would be implemented as two retention features eachhaving one notch each. Terminals 22 of the memory alloy wire actuator 20are coupled to the retention feature 30. In this embodiment, the memoryalloy wire 24 passes from one terminal 22 around an actuation feature42, which is a part of a separate mechanism (not shown), and back to thesecond terminal 22. Actuation feature 42 is movable coupled to a basestructure (not shown) to which retention feature 30 is fixedly coupled.In this example, actuation feature 42 moves in a circular path about apivot point (not shown) of the separate mechanism. The tangent to thiscircular path at the actuation feature 42 is approximately aligned withthe line of action 31. The length of the memory alloy wire 24 can bedivided into a first portion 24A between the first terminal 22 in theactuation feature 42 and a second portion 24B and between the actuationfeature 42 and the second terminal 22. In this embodiment, portions 24Aand 24B are substantially parallel to each other and of the same length.This configuration provides for twice the actuation force of a singlelink of memory alloy wire 24 between the actuation feature 42 and aretention feature 30. In certain embodiments, portions 24A and 24B areat an angle to each other as may be required by the geometry of theinstallation.

In this embodiment, a preload force is applied to the memory alloy wireactuator 20 by actuation feature 42, the force applied in the directionaway from the retention feature 30. The terminals 22 are held inposition against retention feature 30 by this preload force. As theterminals 22 are not held fixedly in place against the surface 32 ofretention feature 30, the terminals 22 can rotate about the line ofcontact between the front faces 26B, 27B and the surface 32. If theterminals 22 were held fixedly in place, as is common to currentapplications of memory wire, and the direction of the memory alloy wire24 at the point of coupling to the terminals 22 was not aligned with theline of action 31, the tension in memory alloy wire 24 caused by thepreload would bend the wire at the edge of terminal 22 and cause a localstress concentration. This stress concentration is detrimental to thelife of current memory alloy wire actuators. The ability of theembodiments of terminal discussed herein to rotate about the line ofcontact allows the terminal to align with the memory alloy wire 24 andavoid this stress concentration, thereby extending the life of thememory alloy wire actuator 20 compared to current designs.

FIGS. 9A-9D illustrate the operation of a self-aligning terminal 22 of amemory alloy wire actuator assembly 40 according to certain aspects ofthis disclosure. FIG. 9A is a cross-section of the retention feature 30through the center of notch 34, where the white region is the notch andthe hatched section below is the cut though the body of retentionfeature 30. Surface 32 is visible as the left edge of retention feature30. Terminal 22 is shown without sectioning. The end of wing 26 isvisible facing the observer and is shaded in FIGS. 9A and 9B to enhanceits visibility. Wing 27 is directly behind wing 26 in this view, and thefront surfaces 26B and 27B are visible as the right edge of wings 26, 27in this view. The line of contact between the front faces 26B, 27B andthe surface 32 is perpendicular to the page in the view of FIG. 9A.

The extended piece 28 is indicated by the dashed line box that includesthe crimp element 29. Memory alloy wire 24 is crimped between the crimpelement 29 and the lower portion of extended element 28. This point ofcoupling between the memory alloy wire 24 and the terminal 22 can beseen to be, in this view, to the right of the line of contact betweenthe front surfaces 26B, 27B of terminal 22 and surface 32 of retentionfeature 30. This is a stable orientation of terminal 22 if the line ofaction 31 from FIG. 8 is aligned with the line of action 44 shown inFIG. 9A, and therefore no stress concentration is created in thisconfiguration.

FIG. 9B illustrates what would happen if a terminal 22X did not rotatewhen the line of action 44A of a memory alloy wire 24X changed. In thisview, the memory alloy wire 24X is deflected and now has a line ofaction 44A that is at an angle to the axis 44 with which the terminal22X remains aligned. It should be emphasized that this situation is notthe behavior of the claimed terminal 22 and memory alloy wire actuator20. Rather, this is what would occur with the fixed terminals of currentmemory wire devices and is presented to emphasize the advantage providedby the claimed terminal 22 and memory alloy wire actuator 20. Since theterminal 22X is at an angle to the memory alloy wire 24X, the memoryalloy wire 24X has a sharp bend at corner 45. There will be a stressconcentration at this corner. Whether this stress concentration isconstant or cyclic, which would be the situation if the line of action44A shifted during each cycle, this is detrimental to the operationallife of memory alloy wire 24X.

FIG. 9C illustrates another termination configuration, wherein the planeof the memory alloy wire 24 is perpendicular to the surface 32 ofretention feature 30 and aligned with the line of action 44 but theplane of the terminal 22 is at an angle to the memory alloy wire 24. Theterminal 22 has pivoted around the front faces 26B, 27B of wings 26, 27.The bend of the memory alloy wire 24 at the front of the extendedelement 28 creates the same stress concentration as present in theconfiguration of FIG. 9B with the same detrimental effect.

FIG. 9D depicts the situation wherein the line of action 31 of FIG. 8 isinclined with respect to the retention feature 30 as indicated by lineof action 44A. The retention feature is not sectioned in FIG. 9D tobetter show the contact between the front surfaces 26B, 27B and surface32. In this situation, a lateral force is applied to the terminal 22 atthe point of coupling between the memory alloy wire 24 and the extendedelement 28 by the tension in the angled memory alloy wire 24. Thislateral force is a downward vertical force in the view of FIG. 9A, andthe resultant opposing force would be an upward vertical force generatedat the line of contact between the front surfaces 26B, 27B and surface32. The combination of the applied lateral force and the resultantopposing force applies a clockwise torque to the terminal 22, causingthe terminal 22 to rotate clockwise about the line of contact betweenthe front surfaces 26B, 27B and surface 32. FIG. 9D depicts the positionof terminal 22 with respect to retention feature 30 after terminal 22has rotated in response to tension in memory alloy wire 24 aligned withline of action 44A. It can be seen that terminal 22 and memory alloywire 24 remain aligned with each other as they have rotated to alignwith line of action 44A. This rotation of terminal 22 prevents aconcentration of stress at the crimp between extended element 28 andmemory alloy wire 24.

While the amount of contraction of the memory alloy wire actuator 20 issmall, there may be motion of actuation feature 42 during thecontraction that produces a change in the angle of the line of action44A. The offset between the point of coupling between the extendedelement 28 and memory alloy wire 24 and the line of contact between thefront surfaces 26B, 27B and surface 32 will always produce a torque onterminal 22 that rotates the terminal 22 to align with the new line ofaction 44A. This self-aligning feature prevents cyclic stress that wouldbe present if the memory alloy wire 24 were to bend at the edge ofextended element 28 with every cycle of contraction, again extending thelife of the memory alloy wire actuator 20 compared to current designs.Cyclic stress can also occur if the angular offset as shown in FIG. 9Bor 9C were to stay constant due to variations of the force on the musclewire acting on the stress concentration where the memory alloy wire 24bends as it meets the terminal 22.

FIG. 10 illustrates an exemplary retention feature 30 configured toposition the self-aligning terminals 22 parallel to and offset from eachother according to certain aspects of this disclosure. This perspectiveview is looking from the terminals 22 along the line of action of thememory alloy wire actuator 20 such that memory alloy wires 24 run up andout of the view. It can be seen that both terminals 22A and 22B areangles such that wing 26 of terminal 22A overlaps wing 27 of terminal22B. This configuration provides a more compact memory alloy wireactuator 20, as the space between the memory alloy wires 24 is reducedcompared to a configuration in which the terminals 22A and 22B do notoverlap. Although the plane of the self-alignment capability of theterminals 22 is also inclined, this has no effect on self-alignment whenthe face 32 of the retention feature 30 is perpendicular to the memoryalloy wire 22, avoiding the situation illustrated in FIG. 9C. The effectin correction is small for the situation of FIG. 9B, provided that theangle of inclination is kept small.

FIG. 11 illustrates an exemplary ADM 100 that includes removable liddedcontainers 1 that include memory alloy wire actuators 20 according tocertain aspects of this disclosure. The ADM 100 includes a cabinet 105with a controller 115 that is, in this example, housed in the topstructure of the ADM 100. The controller includes a processor with amemory (not shown), a display, a keyboard and touchscreen input devices,a power supply (not shown), and communication modules (not shown) thatcouple the processor to the internal components of the ADM and toexternal networks. In certain embodiments, the ADM includes a barcodescanner (not shown) that is fixedly or removably mounted to the topstructure or cabinet. The ADM also includes a drawer 110 that isconfigured to accept the lidded containers 1 from FIG. 1, wherein thelidded containers 1 and the drawer 110 both include complementary matingconnectors that couple the lidded containers to the controller when thelidded containers are accepted by the drawer. The drawer 110 hasmultiple locations 112 configured to accept a lidded container 1. Incertain embodiments, the lidded containers are attached to fixed partsof the cabinet, such as a shelf or inclined surface. In certainembodiments, the lidded containers are not separate from the structureof the cabinet, wherein the equivalent to the body 2 of FIG. 1 isintegrally formed into the structure of the cabinet. In certainembodiments, the equivalent to the body 2 of FIG. 1 is integrally formedinto the structure of the drawer, wherein the compartments formed by thebodies 2 in such a structure have individual lids mounted to the commondrawer structure. In certain embodiments, the cabinet 105 is a smallerstructure having only a few drawers 110, wherein the storage capacity ofthe ADM 100 is suitable for a single patient rather than a plurality ofpatients. In certain embodiments, the cabinet 105 is mounted to andsupported by a wall.

In summary, the disclosed memory alloy wire actuator 20 provides anincreased operational life and increased amount of useable strokecompared to current memory wire devices through the ability toself-align the mechanical terminals 22 with the line of action of thememory alloy wire 24. This self-alignment eliminates stressconcentrations from both misaligned components and cyclic motion of themechanism in operation.

The previous description is provided to enable a person of ordinaryskill in the art to practice the various aspects described herein. Whilethe foregoing has described what are considered to be the best modeand/or other examples, it is understood that various modifications tothese aspects will be readily apparent to those skilled in the art, andthe generic principles defined herein may be applied to other aspects.Thus, the claims are not intended to be limited to the aspects shownherein, but is to be accorded the full scope consistent with thelanguage claims, wherein reference to an element in the singular is notintended to mean “one and only one” unless specifically so stated, butrather “one or more.” Unless specifically stated otherwise, the terms “aset” and “some” refer to one or more. Pronouns in the masculine (e.g.,his) include the feminine and neuter gender (e.g., her and its) and viceversa. Headings and subheadings, if any, are used for convenience onlyand do not limit the invention.

It is understood that the specific order or hierarchy of steps in theprocesses disclosed is an illustration of exemplary approaches. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the processes may be rearranged. Some of the stepsmay be performed simultaneously. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

Terms such as “top,” “bottom,” “front,” “rear” and the like as used inthis disclosure should be understood as referring to an arbitrary frameof reference, rather than to the ordinary gravitational frame ofreference. Thus, a top surface, a bottom surface, a front surface, and arear surface may extend upwardly, downwardly, diagonally, orhorizontally in a gravitational frame of reference.

A phrase such as an “aspect” does not imply that such aspect isessential to the subject technology or that such aspect applies to allconfigurations of the subject technology. A disclosure relating to anaspect may apply to all configurations, or one or more configurations. Aphrase such as an aspect may refer to one or more aspects and viceversa. A phrase such as an “embodiment” does not imply that suchembodiment is essential to the subject technology or that suchembodiment applies to all configurations of the subject technology. Adisclosure relating to an embodiment may apply to all embodiments, orone or more embodiments. A phrase such an embodiment may refer to one ormore embodiments and vice versa.

The word “exemplary” is used herein to mean “serving as an example orillustration.” Any aspect or design described herein as “exemplary” isnot necessarily to be construed as preferred or advantageous over otheraspects or designs.

All structural and functional equivalents to the elements of the variousaspects described throughout this disclosure that are known or latercome to be known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe claims. Moreover, nothing disclosed herein is intended to bededicated to the public regardless of whether such disclosure isexplicitly recited in the claims. No claim element is to be construedunder the provisions of 35 U.S.C. §112, sixth paragraph, unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.” Furthermore, to the extent that the term “include,” “have,” or thelike is used in the description or the claims, such term is intended tobe inclusive in a manner similar to the term “comprise” as “comprise” isinterpreted when employed as a transitional word in a claim.

1. A memory alloy wire actuator comprising: a memory alloy wire havingfirst and second ends; and at least one terminal coupled to one end ofthe memory alloy wire, the terminal comprising two wings and an extendedpiece connected in the shape of a T, the two wings disposed on oppositesides of the extended piece and perpendicular to the extended piece,wherein each wing comprises top and bottom surfaces, a front surface,and an outside end, wherein the top surfaces of the two wings lie in acommon top plane and the front surfaces of the two wings lie in a commonfront plane, and wherein the memory alloy wire is coupled to theextended piece of the terminal.
 2. The memory alloy wire actuator ofclaim 1, wherein the memory alloy wire is coupled to the terminal bycrimping.
 3. The memory alloy wire actuator of claim 1, wherein: thememory alloy wire has a central axis along the center of the wire and anattachment axis that is a straight line that is tangent to the centralaxis at the point where the memory alloy wire is coupled to theterminal; the terminal has an effective cross-section in the commonfront plane, the cross-section extending from the common top plane ofthe wings to a bottom plane that is coincident with the bottom surfacesof the wings and bounded on the sides by the outside ends of the wings;and the extended piece is offset from the common top plane of the wingssuch that the attachment axis of the memory alloy wire passes throughthe effective cross-section of the terminal.
 4. The memory alloy wireactuator of claim 1, further comprising first and second terminalscoupled to the first and second ends of the memory allow wire,respectively.
 5. The memory alloy wire actuator of claim 4, wherein theends of the memory alloy wire extends past the terminals such that theends of the memory alloy wire can be connected to contacts of anelectrical circuit.
 6. A memory wire actuator assembly comprising: amemory alloy wire actuator comprising: a memory alloy wire having firstand second ends; and at least one terminal coupled to one end of thememory alloy wire, the terminal comprising two wings and an extendedpiece connected in the shape of a T, the two wings disposed on oppositesides of the extended piece and perpendicular to the extended piece,wherein each wing comprises top and bottom surfaces, a front surface,and an outside end, wherein the top surfaces of the two wings lie on acommon top plane and the front surfaces of the two wings lie on a commonfront plane, and wherein the memory alloy wire is coupled to theextended piece of the terminal; and a retention feature comprising: aplanar surface; and a notch that passes through the planar surface;wherein the front surfaces of the wings of the terminal contact theplanar surface of the retention feature such that the extended piece ofthe terminal passes through the notch.
 7. The actuator assembly of claim6, wherein the actuator assembly is configured to apply a force to anactuation feature of a mechanism, wherein: first and second terminalsare coupled to the first and second ends of the memory allow wire; theactuator assembly comprises first and second retention features; and thememory alloy wire is configured such that the first and second terminalsare coupled to the first and second retention features, respectively,and the memory alloy wire passes from the first terminal around theactuation feature to the second terminal such that contraction of thememory alloy wire applies force to the actuation feature.
 8. Theactuator assembly of claim 7, wherein the first and second ends of thememory alloy wire extend past the respective terminals such that thememory alloy wire can be connected to contacts of an electrical circuit.9. The actuator assembly of claim 7, wherein the memory alloy wire has afirst portion between the first terminal and the actuation feature and asecond portion between the actuation feature and the second terminal,and wherein the first portion is substantially parallel to the secondportion.
 10. The actuator assembly of claim 9, wherein the first andsecond portions of the memory alloy wire each have a length, the lengthsof the first and second portions being substantially the same.
 11. Theactuator assembly of claim 9, wherein the actuation feature comprises acapstan, wherein the memory alloy wires wrap around a portion of thecapstan and the capstan is configured to not rotate as the rotatingelement moves from the first position to the second position such thatthe memory alloy wire does not slide relative to the capstan.
 12. Theactuator assembly of claim 9, wherein the actuation feature comprises apre-tensioning element configured to apply a force to the actuatorassembly such that the memory alloy wire is continuously under tension.13. The actuator assembly of claim 7, wherein the first and secondretention features and the respective terminals are configured such thatthe planes of the top surfaces of the first and second terminals areparallel to each other.
 14. The actuator assembly of claim 13, whereinthe first and second retention features and the respective terminals areconfigured such that the planes of the top surfaces of the first andsecond terminals are offset from each other.
 15. A self-aligningterminal, comprising: a cross-piece having a center and two wingsconnected to the center and extending in opposite directions from thecenter; wherein the wings each comprise a top surface that lie in acommon top plane; and an extended piece connected to the center of thecross-piece, the extended piece extending perpendicular to the wings;wherein each wing further comprises a front surface facing towards theextended piece wherein the front surfaces of the two wings lie in acommon front plane; and wherein the extended piece is configured tocouple to a memory alloy wire at a point separated from the common frontplane.
 16. The self-aligning terminal of claim 15, wherein the extendedpiece is configured to couple to the memory alloy wire by crimping. 17.The self-aligning terminal of claim 15, wherein: the wings each have anoutside end; the terminal has an effective cross-section that lies inthe common front plane and extends from the top plane of the wings tothe bottom plane of the wings and is bounded on the sides by the outsideends of the wings; and the extended piece has a top surface is offsetfrom the common top plane of the wings such that the cross-section of amemory alloy wire at the point where the memory alloy wire is coupled tothe extended piece, when projected in a direction perpendicular to thecross-section onto the common front plane, overlaps the effectivecross-section of the terminal.
 18. An Automated Dispensing Machine(ADM), comprising: a cabinet; a plurality of lidded containers coupledto the cabinet, each container comprising a securable lid having aclosed position and an open position, and a latch release mechanismconfigured to releasably secure the lid in the closed position, thelatch release mechanism comprising a memory alloy wire actuatorconfigured to cause the latch release mechanism to release the lid fromthe closed position and allow the lid to move to the open position, thememory alloy wire actuator comprising: a memory alloy wire having firstand second ends; and at least one terminal coupled to one end of thememory alloy wire, the terminal comprising two wings and an extendedpiece connected in the shape of a T, the two wings disposed on oppositesides of the extended piece and perpendicular to the extended piece,wherein each wing comprises top and bottom surfaces, a front surface,and an outside end, wherein the top surfaces of the two wings lie on acommon top plane and the front surfaces of the two wings lie on a commonfront plane, and wherein the memory alloy wire is coupled to theextended piece of the terminal; and a controller coupled to the cabinetand the lidded containers, the controller configured to actuate thememory alloy wire actuator of a selected container upon receipt of acommand to open the lid of the selected container.
 19. The ADM of claim18, further comprising at least one drawer slidably mounted in thecabinet, wherein: the lidded containers are removable from the ADM; thedrawer is configured to accept the removable containers; and the liddedcontainers and the drawer each comprise complementary mating connectorsthat couple the lidded containers to the controller when the liddedcontainers are accepted by the drawer.
 20. The ADM of claim 19, whereinthe cabinet is attached to and supported by a wall.